The present invention generally relates to an excess flow check valve that permits fluid flow through a flow line if the flow is below a predetermined flow rate but minimizes the flow line if the flow rate rises above the predetermined limit to prevent uncontrolled flow or discharge of fluids.
Excess flow valves are typically used in a capsule to facilitate its installation in various flow lines, fittings, pipe systems, appliances and the like. The excess flow valve actuates in response to a high or a low differential pressure between the upstream pressure and downstream pressure of the capsule, which usually have four portions, a seat, a housing, a valve plate or body, and a spring or magnet to bias the valve plate. The capsule may be inserted in various flow passageways including a valve body, a connector fitting, a hose fitting, a pipe nipple, a tube, an appliance and other similar installations to provide excess flow protection.
A capsule facilitates assembly of the individual components into a self-contained compact package, provides for easy insertion of the capsule into a fitting or tube, provides means for substantially restricting flow, provides means for allowing small leakage flow for automatic valve resetting, precisely positions and retains the components of the valve for proper operation, provides a unique structure for coupling the two capsule components, permits flow testing as a capsule to verify performance and provides a compact configuration to minimize the size, diameter and length required to accommodate the capsule.
According to an embodiment described herein, a valve for limiting excess flow includes a one-piece body having a seat, a diaphragm, and a plurality of flexible legs attaching the seat to the diaphragm and spacing the seat from the diaphragm, wherein the legs flex to seat the diaphragm within the seat if excess flow exceeds a limit.